Question

我正在使用MongoDB Rust Prototype库，并且正在尝试创建一个聚集阶段。

如何将以下内容转换为Rust聚合阶段？

const aggregationStages = [{
  "$match": {
    "_id": {
      "$in": [ObjectId("5b4289600000000000000000"), ObjectId("5b1afc600000000000000000")]
    }
  },
  "$project": {
    "_id": 1,
    "field": 1,
    "hours": [
      {
        "starts": {
          "$arrayElemAt": ["$times.start", 0]
        }
      }, 
      {
        "ends": {
          "$arrayElemAt": ["$times.end", -1]
        }
      }
    ]
  }
}]

我想我不知道如何将数组转换为有效的Bson文档。

我尝试了以下操作，但有<bson macros>错误。

// get the colelction from the db
let coll = client.db("mydb").collection("places");
let mut aggregation_stages: Vec<bson::Document> = vec![];
let mut aggregation_options = mongodb::coll::options::AggregateOptions::new();
aggregation_options.allow_disk_use = Some(true);
aggregation_options.batch_size = 1000;

let object_ids = ["5b4289600000000000000000", "5b1afc600000000000000000"];
let mut ids: Vec<bson::oid::ObjectId> = vec![];

  for x in object_ids.iter() {
    ids.push(bson::oid::ObjectId::with_string(x).unwrap())
  }

    aggregation_stages.push(doc! { "$match": doc! { "_id": doc! { "$in": ids} }});aggregation_stages.push(doc! {"$project": doc! {
  "_id" : 1,
  "other_field" : 1,
  "hours": [
    doc! { "starts" : doc! {"$arrayElemAt" : ["$times.start", 0]} },
    doc! { "ends" : doc! {"$arrayElemAt" : ["$times.end", -1]} }
  ]
}});

我遇到以下错误：

error[E0277]: the trait bound `bson::Bson: std::convert::From<std::vec::Vec<bson::oid::ObjectId>>` is not satisfied
  --> src\main.rs:111:60
    |
111 |     aggregation_stages.push(doc! { "$match": doc! { "_id": doc! { "$in": ids} }});
    |                                                            ^^^^^^^^^^^^^^^^^^ the trait `std::convert::From<std::vec::Vec<bson::oid::ObjectId>>` is not implemented for `bson::Bson`
    |
    = help: the following implementations were found:
              <bson::Bson as std::convert::From<i32>>
              <bson::Bson as std::convert::From<f32>>
              <bson::Bson as std::convert::From<std::vec::Vec<bson::Bson>>>
              <bson::Bson as std::convert::From<(bson::spec::BinarySubtype, std::vec::Vec<u8>)>>
            and 16 others
    = note: required by `std::convert::From::from`
    = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)

Rust MongoDB：创建{$ in：[ObjectId（“ xxx”）]}

0 个答案: